Laravel Kernel引導流程分析

時間 2019-12-10

標籤 laravel kernel 引導流程分析简体版

原文原文鏈接

Laravel Kernel引導流程分析

代碼展現

protected function sendRequestThroughRouter($request)
{
    # $this->app->instance('request', $request);

    # Facade::clearResolvedInstance('request');
    // 主要是這句代碼
    $this->bootstrap();

    # return (new Pipeline($this->app))
    #            ->send($request)
    #            ->through($this->app->shouldSkipMiddleware() ? [] : $this->middleware)
    #            ->then($this->dispatchToRouter());
}
public function bootstrap()
{
    if (! $this->app->hasBeenBootstrapped()) {
        $this->app->bootstrapWith($this->bootstrappers());
    }
}
protected function bootstrappers()
{
    #####################################################################
    #$bootstrappers = [
    #    \Illuminate\Foundation\Bootstrap\LoadEnvironmentVariables::class,
    #    \Illuminate\Foundation\Bootstrap\LoadConfiguration::class,
    #    \Illuminate\Foundation\Bootstrap\HandleExceptions::class,      
    #    \Illuminate\Foundation\Bootstrap\RegisterFacades::class,
    #    \Illuminate\Foundation\Bootstrap\RegisterProviders::class,      
    #    \Illuminate\Foundation\Bootstrap\BootProviders::class,
    #];
    #####################################################################
    return $this->bootstrappers;
}
public function bootstrapWith(array $bootstrappers)
{
    $this->hasBeenBootstrapped = true;

    foreach ($bootstrappers as $bootstrapper) {
        $this['events']->fire('bootstrapping: '.$bootstrapper, [$this]);

        $this->make($bootstrapper)->bootstrap($this);

        $this['events']->fire('bootstrapped: '.$bootstrapper, [$this]);
    }
}

$this->make($bootstrapper)->bootstrap($this)：會先建立$bootstrapper對象，在執行對象的引導方法，參數爲應用對象php

處理流程

加載並設置應用的系統環境變量(IlluminateFoundationBootstrapLoadEnvironmentVariables)laravel

public function bootstrap(Application $app)
{
    // /var/www/laravel/bootstrap/cache/config.php 存在則直接返回
    if ($app->configurationIsCached()) {
        return;
    }

    $this->checkForSpecificEnvironmentFile($app);

    try {
        // 委託Dotenv來臨時設置這次請求的系統環境變量，默認傳參依次爲'/var/www/laravel'和'.env'
        (new Dotenv($app->environmentPath(), $app->environmentFile()))->load();
    } catch (InvalidPathException $e) {
        //
    }
}
protected function checkForSpecificEnvironmentFile($app)
{
    // cli模式下，而且存在--env參數（相似命令爲： cammond --env=example）
    if (php_sapi_name() == 'cli' && with($input = new ArgvInput)->hasParameterOption('--env')) {
        // 將系統環境文件(相似：/var/www/laravel/.env.example)設置爲$app應用的environmentFile屬性，供後面使用
        $this->setEnvironmentFilePath(
            $app, $app->environmentFile().'.'.$input->getParameterOption('--env')
        );
    }

    if (! env('APP_ENV')) {
        return;
    }

    $this->setEnvironmentFilePath(
        $app, $app->environmentFile().'.'.env('APP_ENV')
    );
}

(new Dotenv($app->environmentPath(), $app->environmentFile()))->load()apache

public function __construct($path, $file = '.env')
{
    // 相似/var/www/laravel/.env
    $this->filePath = $this->getFilePath($path, $file);
    // 建立加載器，委託Loader處理
    $this->loader = new Loader($this->filePath, true);
}
protected function getFilePath($path, $file)
{
    if (!is_string($file)) {
        $file = '.env';
    }

    $filePath = rtrim($path, DIRECTORY_SEPARATOR).DIRECTORY_SEPARATOR.$file;

    return $filePath;
}
public function load()
{
    return $this->loadData();
}
protected function loadData($overload = false)
{
    $this->loader = new Loader($this->filePath, !$overload);

    return $this->loader->load();
}

new Loader($this->filePath, !$overload)bootstrap

public function __construct($filePath, $immutable = false)
{
    $this->filePath = $filePath;
    $this->immutable = $immutable;
}
public function load()
{
    $this->ensureFileIsReadable();

    $filePath = $this->filePath;
    $lines = $this->readLinesFromFile($filePath);
    foreach ($lines as $line) {
        // 若是行不是註釋行且含有=號，則進行
        if (!$this->isComment($line) && $this->looksLikeSetter($line)) {
            $this->setEnvironmentVariable($line);
        }
    }

    return $lines;
}
// 將文件按行的形式讀入到數組並返回
protected function readLinesFromFile($filePath)
{
    $autodetect = ini_get('auto_detect_line_endings');
    ini_set('auto_detect_line_endings', '1');
    $lines = file($filePath, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
    ini_set('auto_detect_line_endings', $autodetect);

    return $lines;
}
public function setEnvironmentVariable($name, $value = null)
{
    // 檢測過濾校驗環境變量
    list($name, $value) = $this->normaliseEnvironmentVariable($name, $value);
    // 當immutable爲真時，不覆蓋對應的環境變量
    if ($this->immutable && $this->getEnvironmentVariable($name) !== null) {
        return;
    }
    // apache運行環境下，嘗試臨時覆蓋系統環境變量
    if (function_exists('apache_getenv') && function_exists('apache_setenv') && apache_getenv($name)) {
        apache_setenv($name, $value);
    }
    // 嘗試臨時設置當前請求的系統環境變量
    if (function_exists('putenv')) {
        putenv("$name=$value");
    }
    // 賦值全局變量
    $_ENV[$name] = $value;
    $_SERVER[$name] = $value;
}

將應用配置文件目錄(/var/www/laravel/config)下全部php文件返回的數組載入到$config對象(IlluminateFoundationBootstrapLoadConfiguration)api

public function bootstrap(Application $app)
{
    $items = [];
    // /var/www/laravel/bootstrap/cache/config.php文件[配置文件的緩存合集，加快加載速度]存在則載入，並標記已加載
    if (file_exists($cached = $app->getCachedConfigPath())) {
        $items = require $cached;

        $loadedFromCache = true;
    }
    // 構建config對象，並注入到服務容器
    $app->instance('config', $config = new Repository($items));

    if (! isset($loadedFromCache)) {
        // 將系統的配置文件載入到$config對象
        $this->loadConfigurationFiles($app, $config);
    }
    // 設置$this['env']爲系統環境變量app.env,沒有則默認爲production
    $app->detectEnvironment(function () use ($config) {
        return $config->get('app.env', 'production');
    });

    date_default_timezone_set($config->get('app.timezone', 'UTC'));

    mb_internal_encoding('UTF-8');
}

$config = new \Illuminate\Config\Repository($items)
public function __construct(array $items = [])
{
    $this->items = $items;
}

protected function loadConfigurationFiles(Application $app, RepositoryContract $repository)
{
    foreach ($this->getConfigurationFiles($app) as $key => $path) {
        // 此操做將在$repository對象裏面構造一個多維數組屬性$this->items，值爲相應的系統配置文件返回的數組，後續能夠直接經過get獲取
        $repository->set($key, require $path);
    }
}
/** $files數組形式以下
    [
        'app' => '/var/www/laravel/config/app.php',
        'auth' => '/var/www/laravel/config/auth.php',
        'xx.file' => '/var/www/laravel/config/xx/file.php',
        'xx.yy.file' => '/var/www/laravel/config/xx/yy/file.php',
    ]
*/
protected function getConfigurationFiles(Application $app)
{
    $files = [];
    // 系統配置文件的路徑(/var/www/laravel/config)
    $configPath = realpath($app->configPath());
    // 文件相關的操做委託給Finder類(很強大)來處理，Finder實現了IteratorAggregate的getIterator方法
    foreach (Finder::create()->files()->name('*.php')->in($configPath) as $file) {
        // 迭代/var/www/laravel/config下面嵌套的層層子目錄構形成.形式的目錄
        $directory = $this->getNestedDirectory($file, $configPath);
        
        $files[$directory.basename($file->getRealPath(), '.php')] = $file->getRealPath();
    }

    return $files;
}

$repository->set($key, require $path)
// 構造將.形式轉變爲相應層級的數組$this->items。好比：$key='xx.yy.file',$value='/var/www/laravel/config/xx/yy/file.php'，將會構建爲:$this->items['xx']['yy']['file'] = $value返回的數組。
public function set($key, $value = null)
{
    $keys = is_array($key) ? $key : [$key => $value];

    foreach ($keys as $key => $value) {
        Arr::set($this->items, $key, $value);
    }
}

根據默認的系統配置文件目錄，以上操做的結果以下：
$config對象（new Repository）裏面的$this->items數組屬性，後期能夠經過$config->get()來獲取數組

$this->items['app'] = /var/www/laravel/config/app.php返回的數組;
$this->items['auth'] = /var/www/laravel/config/auth.php返回的數組;
$this->items['broadcasting'] = /var/www/laravel/config/broadcasting.php返回的數組;
$this->items['cache'] = /var/www/laravel/config/cache.php返回的數組;
$this->items['database'] = /var/www/laravel/config/database.php返回的數組;
$this->items['filesystems'] = /var/www/laravel/config/filesystems.php返回的數組;
$this->items['mail'] = /var/www/laravel/config/mail.php返回的數組;
$this->items['queue'] = /var/www/laravel/config/queue.php返回的數組;
$this->items['services'] = /var/www/laravel/config/services.php返回的數組;
$this->items['session'] = /var/www/laravel/config/session.php返回的數組;
$this->items['view'] = /var/www/laravel/config/view.php返回的數組;

假若有這樣的文件（/var/www/laravel/config/xx/yy/zz/file.php），返回['a'=>'hello,world!']數組
將獲得：$this->items['xx']['yy']['zz']['file'] = ['a'=>'hello,world!'];
獲取方式： $config->get('xx.yy.zz.file.a', $default)，直接返回'hello,world!';

設置應用的錯誤異常等處理事件(IlluminateFoundationBootstrapHandleExceptions)緩存

public function bootstrap(Application $app)
{
    $this->app = $app;

    error_reporting(-1);

    set_error_handler([$this, 'handleError']);

    set_exception_handler([$this, 'handleException']);

    register_shutdown_function([$this, 'handleShutdown']);

    if (! $app->environment('testing')) {
        ini_set('display_errors', 'Off');
    }
}
public function handleError($level, $message, $file = '', $line = 0, $context = [])
{
    if (error_reporting() & $level) {
        throw new ErrorException($message, 0, $level, $file, $line);
    }
}
public function handleException($e)
{
    if (! $e instanceof Exception) {
        $e = new FatalThrowableError($e);
    }

    $this->getExceptionHandler()->report($e);

    if ($this->app->runningInConsole()) {
        $this->renderForConsole($e);
    } else {
        $this->renderHttpResponse($e);
    }
}
// 核心代碼，獲取的\App\Exceptions\Handle對象
protected function getExceptionHandler()
{
    // make時將會直接調用$this->bindings['Illuminate\Contracts\Debug\ExceptionHandler']['concrete'](此代碼位於/var/www/laravel/bootstrap/app.php，應用對象化後，直接注入到服務容器的幾個單例)，返回\App\Exceptions\Handle對象，並將此對象注入到服務容器[參考]
    return $this->app->make(ExceptionHandler::class);
}
protected function renderHttpResponse(Exception $e)
{
    $this->getExceptionHandler()->render($this->app['request'], $e)->send();
}
// \App\Exceptions\Handle
public function render($request, Exception $e)
{
    $e = $this->prepareException($e);

    if ($e instanceof HttpResponseException) {
        return $e->getResponse();
    } elseif ($e instanceof AuthenticationException) {
        return $this->unauthenticated($request, $e);
    } elseif ($e instanceof ValidationException) {
        return $this->convertValidationExceptionToResponse($e, $request);
    }

    return $this->prepareResponse($request, $e);
}
protected function renderHttpException(HttpException $e)
{
    $status = $e->getStatusCode();

    view()->replaceNamespace('errors', [
        resource_path('views/errors'),
        __DIR__.'/views',
    ]);

    if (view()->exists("errors::{$status}")) {
        return response()->view("errors::{$status}", ['exception' => $e], $status, $e->getHeaders());
    } else {
        return $this->convertExceptionToResponse($e);
    }
}
public function handleShutdown()
{
    if (! is_null($error = error_get_last()) && $this->isFatal($error['type'])) {
        $this->handleException($this->fatalExceptionFromError($error, 0));
    }
}

根據配置項設置應用的 Facades(IlluminateFoundationBootstrapRegisterFacades)session

public function bootstrap(Application $app)
{
    Facade::clearResolvedInstances();

    Facade::setFacadeApplication($app);
    // 將配置文件/var/www/laravel/config/app.php返回數組的鍵爲aliases的值賦給\Illuminate\Foundation\AliasLoader的aliases屬性，並進行註冊
    AliasLoader::getInstance($app->make('config')->get('app.aliases', []))->register();
}
public static function clearResolvedInstances()
{
    static::$resolvedInstance = [];
}
public static function setFacadeApplication($app)
{
    static::$app = $app;
}

\Illuminate\Foundation\AliasLoader
public static function getInstance(array $aliases = [])
{
    if (is_null(static::$instance)) {
        return static::$instance = new static($aliases);
    }

    $aliases = array_merge(static::$instance->getAliases(), $aliases);

    static::$instance->setAliases($aliases);

    return static::$instance;
}
private function __construct($aliases)
{
    $this->aliases = $aliases;
}
public function getAliases()
{
    return $this->aliases;
}
public function setAliases(array $aliases)
{
    $this->aliases = $aliases;
}
public function register()
{
    if (! $this->registered) {
        $this->prependToLoaderStack();

        $this->registered = true;
    }
}
protected function prependToLoaderStack()
{
    // 將$this->load註冊到自動加載器的最前面，失敗時拋異常
    spl_autoload_register([$this, 'load'], true, true);
}
public function load($alias)
{
    // $facadeNamespace = 'Facades\\'，估計是框架內部使用的，之後再看吧
    if (static::$facadeNamespace && strpos($alias, static::$facadeNamespace) === 0) {
        $this->loadFacade($alias);

        return true;
    }

    if (isset($this->aliases[$alias])) {
        return class_alias($this->aliases[$alias], $alias);
    }
}

Facade的本質 app

其實是經過$app->make('config')->get('app.aliases', [])取出config/app.php文件裏面的aliases數組並實例化AliasLoader，再將AliasLoader->load方法放到spl自動加載器最前面，最後經過class_alias($this->aliases[$alias], $alias)。當調用Cache::Method時，會觸發Facdes的__callStatic魔術方法，此方法會調用相應對象裏面的方法。框架

注入配置項的服務提供者(IlluminateFoundationBootstrapRegisterProviders)

public function bootstrap(Application $app)
{
    $app->registerConfiguredProviders();
}
public function registerConfiguredProviders()
{
    (new ProviderRepository($this, new Filesystem, $this->getCachedServicesPath()))
                ->load($this->config['app.providers']);
}
public function getCachedServicesPath()
{
    return $this->bootstrapPath().'/cache/services.php';
}

// 先取services緩存文件，再對\Illuminate\Foundation\ProviderRepository進行實例化，隨後加載系統配置文件(./config/app.php)裏面的providers數組
(new ProviderRepository($this, new Filesystem, $this->getCachedServicesPath()))
                ->load($this->config['app.providers'])
public function __construct(ApplicationContract $app, Filesystem $files, $manifestPath)
{
    $this->app = $app;
    $this->files = $files;
    $this->manifestPath = $manifestPath;
}
public function load(array $providers)
{
    $manifest = $this->loadManifest();

    if ($this->shouldRecompile($manifest, $providers)) {
        $manifest = $this->compileManifest($providers);
    }

    foreach ($manifest['when'] as $provider => $events) {
        $this->registerLoadEvents($provider, $events);
    }

    foreach ($manifest['eager'] as $provider) {
        // 直接註冊服務(將直接調用服務的register方法)
        $this->app->register($provider);
    }

    $this->app->addDeferredServices($manifest['deferred']);
}
public function loadManifest()
{
    if ($this->files->exists($this->manifestPath)) {
        $manifest = $this->files->getRequire($this->manifestPath);

        if ($manifest) {
            return array_merge(['when' => []], $manifest);
        }
    }
}
public function shouldRecompile($manifest, $providers)
{
    return is_null($manifest) || $manifest['providers'] != $providers;
}
protected function compileManifest($providers)
{
    $manifest = $this->freshManifest($providers);

    foreach ($providers as $provider) {
        $instance = $this->createProvider($provider);
        // 延遲加載的服務
        if ($instance->isDeferred()) {
            foreach ($instance->provides() as $service) {
                $manifest['deferred'][$service] = $provider;
            }
            // 註冊延遲的事件
            $manifest['when'][$provider] = $instance->when();
        }
        // 即時加載的服務
        else {
            $manifest['eager'][] = $provider;
        }
    }

    return $this->writeManifest($manifest);
}
protected function freshManifest(array $providers)
{
    return ['providers' => $providers, 'eager' => [], 'deferred' => []];
}
public function createProvider($provider)
{
    return new $provider($this->app);
}
public function isDeferred()
{
    return $this->defer;
}
public function writeManifest($manifest)
{
    if (! is_writable(dirname($this->manifestPath))) {
        throw new Exception('The bootstrap/cache directory must be present and writable.');
    }

    $this->files->put(
        $this->manifestPath, '<?php return '.var_export($manifest, true).';'
    );

    return array_merge(['when' => []], $manifest);
}
protected function registerLoadEvents($provider, array $events)
{
    if (count($events) < 1) {
        return;
    }

    $this->app->make('events')->listen($events, function () use ($provider) {
        $this->app->register($provider);
    });
}
public function addDeferredServices(array $services)
{
    $this->deferredServices = array_merge($this->deferredServices, $services);
}

大體流程

經過/var/www/laravel/bootstrap/cache/services.php等實例化IlluminateFoundationProviderRepository，並加載$this->config['app.providers']數組。實例化app.providers各服務提供者，根據其defer屬性將服務進行分類(延遲服務|即時服務)，從而獲得一個$manifest數組(格式如services.php，延遲處理：deferred=>註冊延遲的服務，之後再進行調用；when=>註冊延遲的事件；即時處理：eager=>直接進行註冊調用等)，並從新寫入到services.php，而後根據此文件進行相應的處理。

啓動服務提供者的boot方法等操做(IlluminateFoundationBootstrapBootProviders)

public function bootstrap(Application $app)
{
    $app->boot();
}
public function boot()
{
    if ($this->booted) {
        return;
    }
    // 能夠經過應用的booting方法來註冊服務啓動前的事件監聽者
    $this->fireAppCallbacks($this->bootingCallbacks);
    // 嘗試調用全部的服務提供者的boot方法
    array_walk($this->serviceProviders, function ($p) {
        $this->bootProvider($p);
    });

    $this->booted = true;
    // 能夠經過應用的booted方法來註冊服務啓動後的事件監聽者，若已經啓用了，則直接出發事件
    $this->fireAppCallbacks($this->bootedCallbacks);
}
protected function fireAppCallbacks(array $callbacks)
{
    foreach ($callbacks as $callback) {
        call_user_func($callback, $this);
    }
}
protected function bootProvider(ServiceProvider $provider)
{
    if (method_exists($provider, 'boot')) {
        return $this->call([$provider, 'boot']);
    }
}

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